How to resize the categories images in Magento?

Question

How to resize the categories images in Magento? I used the following code to resize product images, but I'm not able to use it for showing categories images:

$this->helper('catalog/image')->init($_product, 'small_image')->resize(170);

Answer 1

If I am not mistaken, it should be :

init($_product, 'small_image')->resize(100,100);

// single parameter work with 'image'
init($_product, 'image')->resize(100);

// How about this
$this->helper('catalog/image')->init($this->getProduct(), 'thumbnail', $image->getFile())->resize(100,100);

Here is the new code. If you tell me before which extension used, we were solve quickly. If I am not mistaken, you used Template Monster Catalog Image Extension. So, there is a function inside of the extension, like below.

// app/design/frontend/default/default/template/easycatalogimg/homepage.phtml
<?php echo Mage::helper('easycatalogimg/image')->resize($imageUrl, $width , $height) ?>

Answer 2

 <?php
               $_file_name = $cat->getThumbnail(); // Here $cat is category data array                
$_media_dir = Mage::getBaseDir('media') . DS . 'catalog' . DS . 'category' . DS;
                $cache_dir = $_media_dir . 'resize' . DS; // Here i create a resize folder. for upload new category image

if (file_exists($cache_dir . $_file_name)) {
                             $catImg =Mage::getBaseUrl('media') .  'catalog' . DS . 'category' . DS . 'resize' . DS . $_file_name;
                         } elseif (file_exists($_media_dir . $_file_name)) {
                             if (!is_dir($cache_dir)) {
                                 mkdir($cache_dir);
                             }

                             $_image = new Varien_Image($_media_dir . $_file_name);
                             $_image->constrainOnly(true);
                             $_image->keepAspectRatio(false);
                             $_image->keepFrame(false);
                             $_image->keepTransparency(true);
                             $_image->resize(224, 174); // change image height, width
                             $_image->save($cache_dir . $_file_name);
                             $catImg = Mage::getBaseUrl('media') . 'catalog' . DS . 'category' . DS . 'resize' . DS . $_file_name;
                         }
 echo  $catImg ; // display resize category thumbnail imagename
 ?>

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For more clarification see here